Advertisers responsible for spending more than £200m a year with the Sun are standing behind the embattled News International redtop, with the arrest of a number of journalists so far viewed as a "corporate matter" that does not affect their brands.

According to five senior executives at media buying agencies, which negotiate deals with newspaper publishers on behalf of advertisers, there is no sign of an advertiser boycott of the Sun brewing.

"The view is that the arrests have come about as a result of News Corp's own investigative initiative, which is good, and they don't relate to the sensitive area of phone hacking," said one media buying source.

Following the allegations about Milly Dowler's phone being hacked by the News of the World and other claims about illegal activity by the News International paper in July last year, there was a massive advertiser exodus as public pressure mounted for brands to distance themselves from the Sunday tabloid. News International then closed the News of the World on 10 July 2011.

However, the consensus among media buying executives who talked to MediaGuardian is that the Sun is nowhere near a similar situation.

"Advertisers are not yet questioning their commitment to the Sun, although I'm sure some have a watching brief on further developments, unless it becomes a public issue this is viewed as a corporate affair at this stage," said another media buying sector insider.

Paul Hayes, News International's commercial chief, emailed key media buying executives on Monday to remind them not to take any knee-jerk decisions.

"It is important to point out that none of the individuals has been charged and we are clearly not prejudging any outcome," he said in the email, seen by MediaGuardian.

Hayes's correspondence contained a copy of the internal memo sent around by Tom Mockridge, the News International chief executive, at the weekend in which he reminded staff of the "total commitment" the company has to the Sun.

"We are of course continuing to focus on what we do best, which is to publish three world class newspapers; the Sun, the Times and the Sunday Times," said Hayes in his email.

The five largest Sun advertisers are BSkyB, which is 39% owned by News International's parent News Corp, Tesco, Asda, Morrisons and O2, according to unofficial Nielsen Media Research estimates. The Sun accounts for almost 17% of the total UK ad spend on national newspaper advertising.

Several of these, including Asda and Tesco, were in the process of reviewing their commitment to News of the World when Rupert Murdoch made the drastic decision to shut the title last summer.

Top 10 Sun advertisers based on unofficial Nielsen figures for year to end of Jan 2012.

1. BSkyB £17m

2. Tesco £16.7m

3. Asda £13.9m

4. William Morrison Supermarkets £9.7m

5. O2 £6.7m

6. Argos £5.9m

7. DFS £5m

8. Sainsbury's £5m

9. Everything Everywhere £4.6m

10. Vodafone £4m

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